摘要
基于泰勒展开的旅行时公式是计算P波旅行时的一种常用方法。泰勒展开的结果仅在计算点附近准确,而地层中具有垂直对称轴的横向各向同性(transverse isotropy with vertical symmetry axis,VTI)介质进一步放大了旅行时计算的不准确性。本文提出了一种改进的P波旅行时计算方法。该方法以基于泰勒展开的偏移距八阶旅行时方程为基础,利用系数匹配方法分别处理偏移距八阶项与六阶项的系数、偏移距六阶项与四阶项的系数,用整合处理优化得到的参数结构,形成了基于系数匹配与参数整合的偏移距四阶P波旅行时计算方法。水平层状VTI介质模型测试结果表明,该方法能够得到更小的计算误差,保证其在远偏移距处具有较好的表现。三维垂直地震剖面数据实验结果表明,该方法经参数调整后能够进行数据分析,在中偏移距处的表现相对稳定,在远偏移距处具有一定优势。
The traveltime formula based on Taylor expansion is a common method to calculate P-wave traveltime.The Taylor expansion is accurate only near the calculation point,and the inaccuracy of the traveltime approximation is further magnified in the medium of transverse isotropy with vertical symmetry axis(VTI).An improved method for calculating P-wave traveltime is presented in this paper.This method utilizes the 8th-order offset-traveltime equation based on the Taylor expansion,and the coefficient matching method is used to determine the coefficients of the series expansion.Then the integration processing is used to optimize the parameters.Finally,the 4th-order P-wave traveltime calculation method is formed based on coefficient matching and parameter integration.The test results for horizontal layered VTI medium models show that the proposed method has relatively small numerical errors and relatively good performance at the far offset.The experimental results for 3D VSP data show that after parameter adjustment,the method effectively analyzes the data,exhibiting stable performance at middle offsets and a certain advantage at far offsets.
作者
魏建
孙祥娥
Wei Jian;Sun Xiang’e(College of Electronic Information,Yangtze University,Jingzhou 434023,Hubei,China)
出处
《吉林大学学报（地球科学版）》
CAS
CSCD
北大核心
2024年第1期337-344,共8页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(51978078)。
关键词
旅行时计算
系数匹配
参数整合
VTI介质
traveltime calculation
coefficient matching
parameter integration
VTI medium
